As had been said before. The price per case is nothing more than the normal selling price of one bottle times the number of bottles.
1.69 x 24 = $40.56
This is how I think the signs got onto the case: A customer took a case to the register (prior to the price being posted) figuring on paying somewhere around $4 - 8 for the case. The cashier rang up $1.69 a bottle twenty four times and came up with $40.56. This figure infuriated the customer who then caused a scene. The manager came over and the customer tossed some unmentionable names
at the manager. The manager then ordered the sign to be put on the case to eliminate any future outbursts from disgruntled (rightfully so) customers.
Not illegal but, not a classy move.
That's my story and I ain't taking it back.